title: Cu²⁺ sequestration by amine-functionalized silica nanotubes.
abstract: A novel method for Cu(2+) sequestration in Cu(2+) aqueous solution has been demonstrated using amine-functionalized double-walled silica nanotubes (DWSNTs). Herein, the precipitation method and the adsorption method are combined to remove Cu(2+) in the Cu(2+) aqueous solution. Primary (1°), secondary (2°), tertiary (3°), di-, tri-amines are immobilized on the surface of DWSNT as the adsorption site. The results show that the Cu(2+) adsorption amount on the amine-functionalized DWSNTs is in the following order: tri-amine>di-amine>1° amine>2° amine>3° amine. The complexed Cu(2+)s with the amine-functionalized DWSNTs become Cu(OH)2 crystals due to the reaction with OH(-)s dissociated from water. Thus, the amine-functionalized DWSNTs show the superior sequestration capacity of Cu(2+) in the Cu(2+) aqueous solution owing to the Cu(OH)2 crystals growth on them. FT-IR, FEG-SEM, HR-TEM, and XRD studies demonstrate the mechanism of the Cu(2+) adsorption and the Cu(OH)2 crystals growth. The crystallization-technique of the heavy metal ion on the amine-functionalized DWSNTs is also expected to have potential applications such as the facile synthesis of nano- and microparticles, and the metal catalyst supporter.
authors.affiliation: Center for Urban Energy Systems, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea.
authors.forename: Young Gun
authors.initials: YG
authors.lastname: Ko
authors.forename: Hyun Jeong
authors.initials: HJ
authors.lastname: Lee
authors.forename: Hyun Chul
authors.initials: HC
authors.lastname: Oh
authors.forename: Ung Su
authors.initials: US
authors.lastname: Choi
mesh_terms: D000327:Adsorption; D000588:Amines / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D003300:Copper / Q000737:chemistry; D003460:Crystallization; D006863:Hydrogen-Ion Concentration; D007221:Industry; D007477:Ions; D019216:Metals, Heavy; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry; D036103:Nanotechnology; D043942:Nanotubes / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013997:Time Factors; D062065:Wastewater; D014874:Water Pollutants, Chemical / Q000032:analysis; D018508:Water Purification / Q000379:methods; D014961:X-Ray Diffraction
chemical_list: D000588:Amines; D002244:Carbon; D003300:Copper; D007477:Ions; D019216:Metals, Heavy; D012822:Silicon Dioxide; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Adsorbent; Amine type; Aminosilane; Cu(II) ion sequestration; Double-walled silica nanotubes